Introducing Your New Dog to Your Resident Cat
Reprinted from Reach Out Rescue & Resources -
Dogs and cats can usually live together peacefully, although creating a harmonious "blended family" requires some planning, patience, and careful guidance on your part. In some cases your dog and cat will become best friends. When introducing a new dog into your house, you must remember that dogs can kill a cat very easily, even if they are only playing. Sometimes all it takes is one shake by the dog, and the cat’s neck can break. Some dogs have a very high prey drive and should never be left alone with your cat.

When you introduce pets to each other, one of them may send "play" signals that can be misinterpreted by the other pet. If those signals are interpreted as aggression by one animal, then you should handle the situation as "aggressive".

Before bringing a dog into a home with an existing cat, be sure to do the following:
  • Create a safe place for your cat, where the new dog cannot get to it (use a baby gate or a cat door). Your cat should have a "safe" location in every room, even if it is only the top of a bookcase.
  • Put your cat’s litter box in a safe area. Many dogs eat cat feces, and if the dog ambushes the cat in the litter box, the cat may become afraid and relieve himself elsewhere in the house.
  • Keep the cat’s food and water dishes in a safe area as well. Cat food is too rich for dogs, and dog food lacks vital nutrients for cats’ eyesight and heart function.Web Image: Baxter and Stretch3
  • Figure out if your new dog understands basic commands, such as "sit", "stay" and "leave it". This will be helpful with the introductions.
The Introduction:
  • Beforehand, exercise your dog and feed him a nice meal; this will help the dog to get into a relaxed mood.
  • Put the cat in a safe place, and let the dog roam the house for about 30-45 minutes; this allows for the dog to "meet" the cat by smell only. Then take the dog out for a walk and let the cat "meet" the dog by smell only.
  • Put your dog on a short leash, or you can attach the dog’s leash to your belt (for the first few days, if necessary) – this will allow you to make a quick correction if he starts to chase the cat. It will also allow you to bond with your dog… everywhere you go he goes!
  • Put your cat in her carrier if she's typically skittish; otherwise, let her walk around. Be ready with lots of treats for good behavior.
  • The cat’s first reaction will likely be to hiss and/or run… this is perfectly normal.
  • Let dog and cat check each other out at a distance. Pet and talk to your dog soothingly. It's not time for dog to approach cat just yet. Give your dog and cat some treats and praise as rewards.Web Image: Baxter and Stretch1
  • If your dog bolts toward your cat, correct him with the leash, and use the "sit" or "leave it" commands. If he shows any signs of excessive excitability, calm him. If this doesn't do the trick, cut the visit short and try again later. Praise the dog (or give a treat) the moment that he complies and stops trying to get the cat.
  • Repeat these short visits several times a day, gradually giving your dog more leash as appropriate.
Proceed with Caution:
Once your dog and cat consistently get along during leashed visits, you're ready for the next step. Let go of the leash, but be prepared to grab it or step on it if he attempts to go after the cat. If the cat swats the dog on the nose, distract the dog with a toy, but don’t punish the cat. Many times, all it takes is one swat from the cat for a dog to learn his lesson.

Be sure to speak in a calm and soothing voice, and use both animals’ names. If there are any accidents, simply clean it up using an enzymatic cleanser or white vinegar.

Take your dog off the leash, and supervise the two closely. If you see problems, and they don't resolve with a few simple voice commands, go back to the previous phase for a few days. Gradually make the no-leash sessions longer. Do not leave the cat and dog alone until you're sure they're both fully comfortable with each other and there will be no trouble.

Until you know that your dog and cat will be OK when feeding, a trick you can use is to separate them, on either side of a door. This will allow them to associate something enjoyable with the other’s "smell" while eating.

Swap their bedding, so that they will get used to the other’s "smell".

Be sure that the animals are healthy and that you are aware of any medical problems, otherwise this could prolong the introduction process.

If you are introducing a dog into a household with a kitten, use extra caution. A kitten is more likely to be injured by a young, energetic dog or a predatory dog.

When introducing a puppy to a household with a cat, a well-socialized cat will typically be able to deal with a puppy. If you have a shy cat, be more cautious, as a puppy will not understand that the cat does not want to play.

If introductions don’t go smoothly, seek professional help immediately (click here for our Training page). Your pets can be severely injured in fights, and the longer the problem continues, the harder it can be to resolve. Conflicts between pets in the same family can often be resolved with professional help… punishment will not work, and could make things worse.

Now, with all of this in mind, hopefully everything goes very smoothly for you and your pets… so relax and give those guys some hugs!
When introducing any new pet into your home remember that everything will seem strange and frightening to it at first. Even you are unfamiliar and despite your best efforts, can be seen as a source of stress. Here are a few tips to help everyone adjust.

Have all the needed supplies ready before you get your pet. For a dog this will include:
a crate, dishes for food and water, collar and leash, bedding, toys, a quantity of whatever food it has been eating, a quantity of whatever high quality food you intend to feed it, and containment gates.
For a cat the list is the same except for the leash. A cat will also require a litter box, litter, a "nest" of some sort, something to climb on, and a few scratchers.
If you are adopting a pet from a shelter or buying a pet from a breeder, have the shelter or breeder supply a toy or blanket that the animal has used. This provides a familiar smell and a sense of security to your pet. 

Have a designated area set aside where your new pet can be safely confined while adjusting to its new home. Your pet will need time to become accustomed to the new sights, sounds, and smells. A crate placed in a powder room is ideal for a cat, or placed in a quiet corner for a dog. The crate must be large enough for the animal to stand and turn around in comfortably. Your cat will need a crate large enough to hold a litter box while also providing the cat with enough space to  allow it room away from the litter.
While you will be eager to fuss over your new pet, he or she might need time to become comfortable with all of this new attention. Keep their tolerance for new stimuli in mind.
The first night with your dog will be awful. It will likely cry all night. Place a familiar toy or blanket in its crate. A radio or white noise machine set on low volume can provide comfort. Do NOT give in to the temptation to put the animal in your bed. Once it has slept in your bed, it will NEVER want to sleep anywhere else. This might sound OK until you have spent the night with a 50 pound dog tossing, turning, kicking, snoring, scratching, passing gas, and stealing your blankets all night long. Teach it to sleep in its crate. 
Most pets will eat twice a day. Mix whatever food the pet has been eating half and half with whatever food you will be feeding in the future. This allows the animal's digestive system to adapt to the new food with a minimum of vomiting and/or diarrhea.
Take your dog outside first thing in the morning, after it eats or drinks, after play, and before bed. You really cant take it out too often. Keep it outside until it "goes" then praise it as if it has done the most wonderful thing. Crating your dog is not cruel. Dogs are den animals and find comfort in having their own space. Crating will also greatly reduce the time required to housebreak. 
Speaking of housebreaking, accidents will happen. Punishing your dog for an accident after the fact is useless as the animal will have no idea what it did wrong. "Rubbing his nose in it" will lead to confusion and fear. If you catch your dog "in the act", immediately rush him or her outside to finish the deed. Then praise with enthusiasm.
Once your cat is comfortable being fed and handled by you (normally just a few days), you can remove the crate and turn it loose in the powder room or bathroom where the crate was kept. A couple of days after this you can give it the run of the house. It will likely slink around for a bit, getting the lay of the land. It will probably hide under furniture until it has fully assessed the safety of its new home. Give it time to adapt.
Declawing is painful and deforming. It also leads to litter box problems. If you keep a number of scratchers around the house, you shouldn't have any problem with damage to curtains or furniture.  Begin trimming claws at an early age to get them used to having it done.
Dogs need to be socialized from an early age. Take it on walks where it can see other people. Many stores welcome well behaved pates. PetSmart, Lowes, and Home Depot are pet friendly. These outings will make for a well adjusted dog.
Remember, your new pet has been brought into a strange environment and has no idea what is going on nor does it have any idea what is expected of it. It is your responsibility to ensure that it becomes a happy, healthy, well behaved pet that is a joy to own.
Is the cat obviously sick or injured? Does it appear to be relatively well fed? Is the tip of its left ear missing? Stray cats, sometimes called community cats or neighborhood cats, are opportunistic. If the cat(s) appears to be well fed, that means that it has a nearby source of food. That might be vermin such as mice and rats, but most likely, there is a neighbor who is providing food. If the cat is missing the tip of its left ear, that means that it has been spayed or neutered and will not likely be engaged in nuisance activities such as yowling, fighting, mating, or spraying.
If you would like the cat to settle somewhere else, simply make sure that there are no sources of food available and seal off any access points to your cellar, crawl space, garage, or shed. If the cat is unusually persistent, installing a deterrent such as a motion activated sprinkler might be required.
Please don't call Animal Control to come trap the cat to remove it unless it is obviously sick or injured. Stray cats trapped by Animal Control are taken to the county shelter. Because these cats are not tolerant of being handled by people they can not be adopted and are euthanized. These cats also place an additional burden on shelter staff and consume limited resources required for euthanasia and disposal.
Another reason to avoid trapping these cats is that you might be separating kittens from their mother. Cats can and will have kittens at any time of year. Without their mother to feed and protect them, kittens born outdoors face serious perils such as exposure, starvation, and predation.
If you find kittens outdoors, leave them where they are. The mother is probably nearby. However, keep an eye on them. If the kittens are tiny and their eyes aren't open yet, the mother won't stay away for more than a couple of hours. if the kittens are active, they can be left alone for a full day or longer.  If their mother doesn't show up for a full day and the kittens are becoming lethargic, its time to take action. Young kittens are very fragile and require special foods. The milk in your fridge will not keep them alive. Do not take them to the shelter. Their undeveloped immune systems make them extremely vulnerable to the illnesses that thrive in a shelter environment. Take the kittens to a veterinarian or call The Spay Neuter Project.
Unless the cat is in obvious distress the best course of action is to leave it  where it is. These cats are quite capable of surviving on their own outdoors. If you simply can"t tolerate having it hang out at your place, try the steps mentioned above. Please don"t ensure its destruction by having it taken to the animal shelter.